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authorKees Cook <keescook@chromium.org>2011-11-17 12:58:07 -0800
committerTony Luck <tony.luck@intel.com>2011-11-17 12:58:07 -0800
commitf6f8285132907757ef84ef8dae0a1244b8cde6ac (patch)
treef3d3b37349e79251cfe16ef0f39e0b4af1a266b1 /fs/pstore
parentcfcfc9eca2bcbd26a8e206baeb005b055dbf8e37 (diff)
downloadop-kernel-dev-f6f8285132907757ef84ef8dae0a1244b8cde6ac.zip
op-kernel-dev-f6f8285132907757ef84ef8dae0a1244b8cde6ac.tar.gz
pstore: pass allocated memory region back to caller
The buf_lock cannot be held while populating the inodes, so make the backend pass forward an allocated and filled buffer instead. This solves the following backtrace. The effect is that "buf" is only ever used to notify the backends that something was written to it, and shouldn't be used in the read path. To replace the buf_lock during the read path, isolate the open/read/close loop with a separate mutex to maintain serialized access to the backend. Note that is is up to the pstore backend to cope if the (*write)() path is called in the middle of the read path. [ 59.691019] BUG: sleeping function called from invalid context at .../mm/slub.c:847 [ 59.691019] in_atomic(): 0, irqs_disabled(): 1, pid: 1819, name: mount [ 59.691019] Pid: 1819, comm: mount Not tainted 3.0.8 #1 [ 59.691019] Call Trace: [ 59.691019] [<810252d5>] __might_sleep+0xc3/0xca [ 59.691019] [<810a26e6>] kmem_cache_alloc+0x32/0xf3 [ 59.691019] [<810b53ac>] ? __d_lookup_rcu+0x6f/0xf4 [ 59.691019] [<810b68b1>] alloc_inode+0x2a/0x64 [ 59.691019] [<810b6903>] new_inode+0x18/0x43 [ 59.691019] [<81142447>] pstore_get_inode.isra.1+0x11/0x98 [ 59.691019] [<81142623>] pstore_mkfile+0xae/0x26f [ 59.691019] [<810a2a66>] ? kmem_cache_free+0x19/0xb1 [ 59.691019] [<8116c821>] ? ida_get_new_above+0x140/0x158 [ 59.691019] [<811708ea>] ? __init_rwsem+0x1e/0x2c [ 59.691019] [<810b67e8>] ? inode_init_always+0x111/0x1b0 [ 59.691019] [<8102127e>] ? should_resched+0xd/0x27 [ 59.691019] [<8137977f>] ? _cond_resched+0xd/0x21 [ 59.691019] [<81142abf>] pstore_get_records+0x52/0xa7 [ 59.691019] [<8114254b>] pstore_fill_super+0x7d/0x91 [ 59.691019] [<810a7ff5>] mount_single+0x46/0x82 [ 59.691019] [<8114231a>] pstore_mount+0x15/0x17 [ 59.691019] [<811424ce>] ? pstore_get_inode.isra.1+0x98/0x98 [ 59.691019] [<810a8199>] mount_fs+0x5a/0x12d [ 59.691019] [<810b9174>] ? alloc_vfsmnt+0xa4/0x14a [ 59.691019] [<810b9474>] vfs_kern_mount+0x4f/0x7d [ 59.691019] [<810b9d7e>] do_kern_mount+0x34/0xb2 [ 59.691019] [<810bb15f>] do_mount+0x5fc/0x64a [ 59.691019] [<810912fb>] ? strndup_user+0x2e/0x3f [ 59.691019] [<810bb3cb>] sys_mount+0x66/0x99 [ 59.691019] [<8137b537>] sysenter_do_call+0x12/0x26 Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'fs/pstore')
-rw-r--r--fs/pstore/platform.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 2bd620f..57bbf90 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -167,6 +167,7 @@ int pstore_register(struct pstore_info *psi)
}
psinfo = psi;
+ mutex_init(&psinfo->read_mutex);
spin_unlock(&pstore_lock);
if (owner && !try_module_get(owner)) {
@@ -195,30 +196,32 @@ EXPORT_SYMBOL_GPL(pstore_register);
void pstore_get_records(int quiet)
{
struct pstore_info *psi = psinfo;
+ char *buf = NULL;
ssize_t size;
u64 id;
enum pstore_type_id type;
struct timespec time;
int failed = 0, rc;
- unsigned long flags;
if (!psi)
return;
- spin_lock_irqsave(&psinfo->buf_lock, flags);
+ mutex_lock(&psi->read_mutex);
rc = psi->open(psi);
if (rc)
goto out;
- while ((size = psi->read(&id, &type, &time, psi)) > 0) {
- rc = pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
+ while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
+ rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
time, psi);
+ kfree(buf);
+ buf = NULL;
if (rc && (rc != -EEXIST || !quiet))
failed++;
}
psi->close(psi);
out:
- spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+ mutex_unlock(&psi->read_mutex);
if (failed)
printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
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